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为减少激光深熔焊接铝合金过程中产生的冶金型气孔和小孔型气孔,达到提高工件力学性能的目的,系统分析激光功率、焊接速度以及离焦量等工艺参数分别对两种气孔造成的影响,同时观察不同焊接参数下小孔上方的金属蒸汽羽烟形状与波动情况,以反映焊接过程中小孔的稳定性。结果显示,增加激光功率或减小激光光斑半径时,小孔上方金属蒸汽羽烟波动剧烈,形状和大小都极不稳定,间接反映小孔的稳定性更差,因此在焊缝根部产生更多小孔型气孔。当由激光能量密度变化引起的小孔深宽比增高时,小孔内部坍塌的可能性升高,并在焊缝中留下更多的气孔。当激光功率为5 k W、离焦量为0、焊接速度为2.0 m/min时,气孔率达到最小值。
In order to reduce the metallurgical pores and small holes in the aluminum alloy during deep penetration laser welding and achieve the purpose of improving the mechanical properties of the workpiece, the laser power, welding speed and defocusing power were systematically analyzed. While observing the shapes and fluctuations of metal vapor plume above the small holes under different welding parameters to reflect the stability of the small holes in the welding process. The results show that when the laser power is increased or the radius of the laser spot is increased, the plume of metal vapor above the small hole fluctuates violently, and its shape and size are extremely unstable, which indirectly shows that the stability of the small hole is worse. Small hole type stoma. As the aspect ratio of the aperture due to laser energy density changes increases, there is an increased likelihood of collapse within the aperture and more pores in the weld. When the laser power is 5 k W, the defocus amount is 0 and the welding speed is 2.0 m / min, the porosity reaches the minimum value.